Well casing perforating gun and cartridge



Dec. 21, 1948..

V J- M CULLOUGH WELL mm PERFORATING GUN AND CARTRIDGE Filed Nov. 1, 1941 E c c Sumter, [BA J Ma 6141.006

of an external wall portion Patented Dec. 21, 1948 v WELL CASING PERFORATING GUN AND CARTRIDGE Ira J. McCullough, Los Angeles, Calif., ass'ignor to McCullough Tool Company, Los Angeles, Caliih, a corporation of Nevada Application November 1, 1941, Serial No. 417,418

4 Claims. 1 1

My invention relates to a cartridgeincluding a shell, bullet, and powder-charge, having a wide range of usefulness, and which may be advantageously used in a gun for perforating casing within a well or for shooting projectiles into the formation surrounding the well bore.

It is an object of the invention to provide a cartridge of novel form having therein a selfcontained gun barrel.

A further object of the invention is to provide a cartridge so formed that the force of the explosion of the powder charge acts to retard the outward movement of the projectile while a high pressure of products of combustion are built up in the powder chamber and against the rear end of the projectile so thatwhen the projectile is finally released it will be propelled at maximum velocity.

A further object of the invention is to provide a cartridge having a tubular portion to receive the projectile and a powder chamber in the cartridge laterally disposed with relation to the portion occupied by the projectile, thereby producing a cartridge which is relatively short for the size of bullet and powder charge used therein.

A further object of the invention is to provide a cartridge having a shell with an outer wall and a projectile receiving tube or barrel disposed inside the space defined by the outer wall and in spaced relation thereto so as to provide a powder chamber, at least a part of which surrounds the projectile tube or barrel.

A further object of the invention is to provide means for preventing movement of the projectile as the result of external hydrostatic pressure exerted thereagainst in a deep well.

A further object of the invention is to provide a cartridge having a projectile andmeans for concealing and protecting the projectile from externally applied pressure, this means comprising a wall which is pentrated by the projectile when it is propelled outward as a result of the explosion of the powder charge. v

' A further object of the invention is to provide a cartridge having a detonator or cap so placed that it is protected against external contact and resulting accidental ignition of the powder charge.-

A further object of the invention is to provide a cartridge having a detonator or capso placed that it can be set off only by inward movement of the shell of the cartridge.

A further object of the invention is to provide a cartridge which is not only suitable for submarine use, but also in guns of various types, and especially guns with short barrels.

Further objects and advantages of the invention will be brought out in the following part of the specification.

Referring to the drawing-s which trative purposes only:

Fig. 1 is a vertically sectioned view showing a are for illusportion of the gun with a preferred embodiment of the cartridge therein.

Fig. 2. is an enlarged longitudinal section of the cartridge. p

Fig. 3 is a cross-section taken on thegplane represented by the line 3-3 of Fig. 2.

The cartridge l0 shown as a preferred embodiment of my invention comprises a shell or casing ll, a projectile or bullet l2 and a powder charge l'3. In this specification and in the claims, the term powder is intended to designate all of the explosives usable for the purpose of propelling the projectile.

The casing ll includes an outer wall M which is of tubular form and preferably cylindrical, although it may be slightlytapered; Within the outer wall N there is a tube l5 which may be referred to as a barrel. This tube I5 is spaced from the outer wall l4 and is preferably coaxial therewith. It provides a bore Hi to receive a projectile l2 which comprises a cylindrical body of hard metal; such as steel alloy, having a point I! on its front end and having a small point l8 projecting centrally from its rear end face.

The rear end of the bullet and the rear end I9 of the tube [5 are spaced from the plane defined by a shoulder 20 formed in the rear end of the outer wall It. The tube 15 comprises a rear section 2| having a length nearly as great as the length of the body of the projectile l2, and a front section 22. The rear section 2| of the tube 55 comprises a relatively thin wall, for a purpose which will be hereinafter described, and the front section 22 comprises a thicker wall which is joined by an annular front wall 23 with the front end of the outer wall Id. The front end of the bore l5 of the tube or barrel I5 is closed by a wall 2t, this wall isolating the bore from the exterior of the cartridge and guarding the front end of the projectile against externall applied hydraulic pressures such asencounteredin deep wells,thereby assuring that the bullet will not be forced rearward or leftward from the position in which it is shown 3 in Fig. 2, to prematurel fire the cartridge as the result of the engagement of the point is with a firing device 26'supported in a rear wall 21 in 'axial alignment with the point or firing pin it.

Therear wall comprises a metal disc, slightly dished and having on the inner face a projecting annular-wall 21' forming a recess to receive the firing device 26 which may be a cap or a fulminate of mercury detonator such as used in shot gun, revolver and rifle cartridges, The peripheral portion of the wall 21 rests against the shoulder at the rear end of the outer wall l4 and is adapted to be placed in the position shown after the projectile l2 has been placed in the barrel l5 andthe powder charge has been placed in the powder chamber 29, comprising the annular space between the outer wall l4 and the tube I5 and the space between the rear end of the projectile l2 and the rear wall 21. When the rear wall 21 is finally placed against the shoulder 20, an annular lip. which surrounds the shoulder 20 is rolled in so as to engage the slightly chamfered edge wall 3| of the rear end wall or disc 21.

In Fig. 1 I have shown a gun body 32 forming part of a gun adapted to be lowered into a well n by use of suitable suspension means, such as, for example, a string of tubing, a portion of which is shown at 33. The gun .body 32 has one or more bores 34 extending in from the side wall to form cartridge chambers 35 and adjacent internally threaded sections to receive cartridge securing means 31, comprising externally threaded plugs with axial openings 38 of substantially the same diameter as the bore i6 of the cartridge Ill, these openings '38 comprising barrels or barrel extensions for the barrels l5 of the cartridges.

A vertical passage 39 extends within the gun body 32 in spaced relation to the rear end of each cartridge chamber 35, and this vertical passage 39 is connected with the rear ends of the chambers 35 by ports 40. The upper end of the vertical passage 339 communicates with a firing charge chamber 4| through passage means 42, thisflring charge chamber 4| being closed by removable plug 42, enabling access to the chamber 4!, whereby a firing charge 43 of powder may be placed in the chamber 4|.

Above the firing charge chamber 4| there is a removable block 44 adapted to carry a priming device 45 in a vertical opening 46, the lower-end of which is connected through a passage 41 with the upper portion of the firing charge chamber 4 I. A firing pin 48 is arranged above the priming device 45 and is normally held in raised position by a spring 49 and a shear pin 50 disposed below a head 5| supported on the upper end of the firing pin 48 above the upper end 52 of the gun body, where it may be engaged by suitable actuating means such as a weight or go-devil adapted to strike the head 5| to drive the firing pin 48 downward so that the point at the lower end thereof will engage the priming device 45 and fire the same.

The blast or flame issuing downward from the priming device 45, which ordinarily may consist of a small blank cartridge, passes into the firing charge chamber 4| and ignites the firing charge 43, which is of sufilcient size to produce a heavy pressure or explosive force in the passage 39 which will be transmitted through the ports 40 into the rear ends of the cartridge chambers 35 and into engagement with the pins l8 to explode the firing device 26 and thereby ignite the powder charges I3 in the cartridges Ill.

As previously set forth herein, the rear section 2| of the tube or barrel l5 comprises a relativel thin wall. The diameter of the bullet i2 is greater than the diameter of the bore [6 so that the bullet must be pressed into place, placing the wall of the rear section 2| under tension so that it will tightly grip the body of the projectile I2. As the burning of the powder charge i3 proceeds, the pressure of a gas will be built up in the powder charge chamber 29 of the cartridge i0, and, since the pressure of this gas acts in all directions, radial inward force will be applied exter-' nally to the section 2| of the tube I5 as indicated by arrows 55 in Fig. 3, causing the wall section 2| to grip the projectile l2 with greater force, so as to retard outward movement of the projectile in the bore l6 while a heavy pressure is being built up in the chamber 29 of the cartridge ID, the result being that when the projectile i2 is propelled outwardly, the pressure behind the same will be close to the maximum of which the powder charge I3 is capable, and accordingly the projectile |2 will be moved outwardly at high velocity, ruptur ing or shearing the guard wall 24 and then passing through the barrel extension 38, Fig. 1, to the exterior.

It will be noted that the cross-sectional area of the powder charge chamber 29 is quite large as compared to the cross-sectional area of the projectile l2, and that therefore the cartridge I4,

I although it is relatively short, will carry a much heavier charge of powder than the common style of cartridge for the same size of bullet having the shell or casing extended rearward from the projectile. For a half-inch diameter bulet, it is possible to make a cartridge in accordance with my invention having a length of one and threequarters to two and one-eighth inches, which will carry a powder charge of two hundred grains, determined in,actual practice of well perforating to be the maximum amount of powder required for any of the uses or penetration required of a halfinch bullet, such as shown approximately to scale in Fig. 2.

I claim as my invention:

1. In a. well casing perforating gun of the character described: a gun body having a chamber for a primary firing charge, means to ignite the flring charge, a duct leading away from said firing charge chamber, and a cartridge chamber connected to said duct so as to receive fluid pressure resulting from the burning of said firing charge; a removable wall closing the front end of said cartridge chamber and having a bore therein for passage of a projectile to the exterior; and a cartridge in said cartridge chamber, said cartridge comprising a shell having a wall movable relatively to the remaining walls of the cartridge by externally applied fluid pressure, an opening with a projectile therein aligned with said bore, a

powder chamber with a propelling powder charge I therein and means acting in response to movement of said movable wall by said fluid pressure to ignite said powder charge.

2. In a well casing perforating gun of the character described: a gun body having a chamber for a primary firing charge, means to ignite the firing charge, aduct leading away from said flring charge chamber, and a cartridge chamber connected to said duct so that its rear end'will receive fluid pressure resulting from the burning of said firing charge; a removable wall closing powder chamber, a projectile in the inner end of saidbarrel, a propelling powder charge in said powder charge chamber, and means acting in response to movement of said movable wall by said fluid pressure to ignite said powder charge.

3'. In a well casingperforating gun of the character described: a gun body having a chamber for a primary firing charge, means to ignite the firing charge, a duct leading away from said firing charge chamber, and a cartridge chamber connected to said duct soas to receive fluid pressure resulting from the burning of said firing charge; a removable wall closing the front end of said cartridge chamber and having a bore therein for passage of a projectile to the exterior; and a cartridge in said cartridge chamber, said cartridge comprising a shell having a wall movable relatively to the opposite wall of the cartridge by externally applied fluid pressure, a tubular barrel aligned with said bore and extending into said shell from the front end thereof and forming in said shell an annular powder chamber, a projectile in the inner end of said barrel, a propelling powder charge in said powder charge chamber, and pressure responsive igniting means disposed between said rear end wall and the rear end of said projectile so as to be compressed as the resultof the movement of said rear end wall of said shell.

4. In a well casing perforating gun of the character described: a gun body having a chamber for a primary firing charge, means to ignite the firing charge, a duct leading away from said firing charge chamber, a bore having a projectile at the inner end thereof, a transverse wall in said bore in a position spaced from the outer end of said bore, the periphery of said transverse wall powder charge chamber from said duct, said wall being so formedthat it will be flexed toward said powder charge chamber by fluid pressure transmitted through said duct as the result of the burning of said firing charge, and' means acting in response to the fi'exing of said wall by said fluid pressure to ignite said powder charge.

' IRA J. McCULLOUGI-I.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 3,833 White Feb. 8, 1870 44,692 Sneider Oct; 11, 1864 542,540 Simpson July 9, 1895 624,146 Young May 2, 1899 625,440 Elliot May 23, 1899 895,558 Harris Aug. 11, 1908 1,107,519 Hoagland Aug. 18, 1914 1,166,360 Gregory Dec. 28, 1915 1,336,656 Rogezea.- Apr. 13, 1920 1,470,591 Behar Oct. 16, 1923 1,589,194 Maxwell June 15, 1926 1,835,722 Rembert Dec. 8,1931 1,856,022 Blacker Apr. 26, 1932 2,041,209 Ridley May 19, 1936 2,169,671 Walker Aug. 15, 1939 2,200,683 Schlumberger May 14, 1940 2,210,192 Turechek ..Aug. 6, 1940 2,250,056 Alexander July 22, 1941 2,297,041 Wellington Sept. '29, 1942 2,358,951 Turechek Sept. 26, 1944 FOREIGN PATENTS Number Country Date 14,348 Great Britain 1918 18,238 Germany une 7, 1882 392,329 Great Britain May 18, 1933 642,754 Germany Mar. 13, 1997 municating with the rear end of said bore, a.

powder charge therein, a wall separating said 

